The introduction of a 5'-deoxy substituent into pyrimidine nucleosides has been previously described. Thus Wempen et al., J. Amer. Chem. Soc. 82, 1624 (1960) reported the synthesis of 5'-deoxy-uridine, 5'-deoxy-5'-fluoro-cytidine, and 5'-deoxy-5'-fluorouridine. Japanese Pat. No. 49-116081 describes the preparation of 5'-deoxy-cytidine by reduction of corresponding 5'-halo (Br or I) or 5'-methyl or benzylmercaptans. No anti-tumor activity was ascribed to either of the aforementioned final product compounds.
Falco and Fox, J. Med. Chem. 11, 148 (1968) describe the synthesis of 1-(5'-deoxy- .beta.-D-arabinofuranosyl) cytosine. This compound was found to be inactive against L1210, leukemia and Burkitt's cell cultures presumably because such compound could not form a 5'-phosphorylated derivative.
Hein et al., Nucleic Acids Research 3, 1125 (1976) also have prepared 5'-deoxyuridine and 2',5'-dideoxyuridine by alternate reductive procedures. No biological activity is ascribed to the products produced.
Japanese Pat. No. 51-086481 discloses the preparation of 2',5'-dideoxy-5-fluorouridine from the corresponding 2',5'-dideoxy-5'-iodo compound. The product is indicated to be an anti-cancer agent inhibiting the growth of Yoshida sarcoma.
U.S. Pat. No. 3,687,931 teaches the preparation of 5'-deoxy-5'-chloro or bromo nucleosides using triphenylphosphine using carbon tetrachloride or carbon tetrabromide. The compounds are disclosed to have antibiotic, antimetabolic and enzyme inhibition activity.